Thread wiper

ABSTRACT

A sewing machine thread-wiping mechanism includes a pair of vertically extending parallel guide arms disposed rearwardly and above the reciprocating path of the sewing needle tip, one of the guide arms having a linear first slot and the other arm having a slot with an upper portion parallel to the first slot and an angulated lower portion. A pneumatic cylinder reciprocated slide member is located between the guide arms and carries a first follower engaging the first slot and a transverse rockable shaft provided with a crank arm carrying a second follower engaging the second slot. A picker arm extends radially from the shaft and terminates in a hook which, with the lowering and raising of the slide member, moves downwardly, forwardly, and rearwardly across the needle path, and then upwardly.

United States Patent [1 1 Rosa [451 Aug. 26, 1975 THREAD WIPER [75] Inventor: Salvatore Rosa, l-lackensack, NJ.

[73] Assignee: Clinton Industries, Inc.,

Hackensack, NJ.

[22] Filed: Aug. 5, 1974 [21] Appl. No.: 494,519

[52] U.S. Cl. 112/252 [51] Int. Cl. D05B 65/00 [58] Field of Search 1 12/252, 241-247 [56] References Cited UNITED STATES PATENTS 3,498,243 3/1970 Aoyama 112/252 3,749,041 7/l973 Bowin 112/252 3,847,102 1 H1974 Rogner 112/252 Primary ExaminerGeo. V. Larkin Attorney, Agent, or FirmWilliam R. Liberman, Esq.

[ 5 7 1 ABSTRACT A sewing machine thread-wiping mechanism includes a pair of vertically extending parallel guide arms disposed rearwardly and above the reciprocating path of the sewing needle tip, one of the guide arms having a linear first slot and the other arm having a slot with an upper portion parallel to the first slot and an angulated lower portion. A pneumatic cylinder reciprocated slide member is located between the guide arms and carries a first follower engaging the first slot and a transverse rockable shaft provided with'a crank arm carrying a second follower engaging the second slot. A picker arm extends radially from the shaft and terminates in a hook which, with the lowering and raising of the slide member, moves downwardly, forwardly, and rearwardly across the needle path, and then upwardly.

6 Claims, 5 Drawing Figures THREAD WIPER BACKGROUND OF THE INVENTION The present invention relates generally to improvements in sewing machines and it relates particularly to an improved thread wiping mechanism for withdrawing the severed thread from the path of the work piece following the application of a line of stitching.

In performing commercial sewing operations, it is necessary for maximum economy and efficiency to reduce to a minimum the number of time-consuming hand operations. Among such operations ordinarily manually performed and highly time consuming is the removal of the severed thread from the path of a work piece following the completion of a sewing sequence so as to facilitate the unhindered performance of the following sewing sequence. Many thread-wiping or retracting mechanisms for performing the above thread withdrawal operation have been available and proposed, but these possess numerous drawbacks and disadvantages. They are complicated and unreliable devices, difficult to mount on the conventional sewing machine without interfering with the operation thereof, are of little versatility and adaptability, and otherwise leave much to be desired.

SUMMARY OF THE INVENTION It is a principal object of the present invention to provide an improved sewing machine mechanism. Another object of the present invention is to provide an improved sewing machine thread wiping mechanism.

Still another object of the present invention is to provide an improved sewing machine thread wiping mechanism for withdrawing the severed thread from the path of a work piece upon the termination of a sewing sequence.

A further object of the present invention is to provide a mechanism of the above nature characterized by its reliability, ruggedness, simplicity, ease of application and high versatility and adaptability.

The above and other objects of the present invention will become apparent from a reading of the following description taken in conjunction with the accompanying drawings which illustrate a preferred embodiment thereof.

In a sense, the present invention contemplates the provision, in a sewing machine including a reciprocating needle, of a thread-wiping mechanism comprising a picker member including a hook element having a rearwardly directed opening and activating means located rearwardly of and above the reciprocated path of the needle point and supporting the picker member for successively lowering the picker member toward the needle path, rocking the picker member to advance and retract the hook member across the needle path and then retracting and raising the picker member above the lower end of the raised needle. In the preferred form of the improved mechanism, the actuating means includes a pair of transversely spaced, parallel, vertically extending tracks having formed therein first and second guide slots with parallel upper sections, the first slot having a cam-defining lower section angularly related to the slot upper sections, a slide member between said tracks, a transverse shaft joumalled to the slide member, a crank arm mounted on the shaft and carrying a first follower engaging the first slot, a second follower on the slide member engaging the second slot, the picker member including an arm extending radially from the shaft and terminating in the hook member, and means for reciprocating the slide member along the tracks.

The improved thread-wiping mechanism is highly reliable, simple, rugged, easy to apply and use, and of great versatility and adaptability.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front perspective view of a sewing machine head provided with a thread retracting mechanism embodying the present invention; FIG. 2 is a fragmentary end view thereof illustrating the thread retractor in its retracted condition;

FIG. 3 is a view similar to FIG. 2 showing the retractor in its advanced condition;

FIG. 4 is an exploded perspective view of the thread retractor mechanism; and

FIG. 5 is a rear elevational view, partially in section, of the assembled mechanism.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings which illustrate a preferred embodiment of the present invention, reference numeral 10 generally designates the improved thread retractor or wiper mechanism illustrated, applied to a sewing machine head 11 of conventional construction. The sewing machine head 11 includes at its outer end a vertically reciprocating needle 13. A rockable presser foot 15 is mounted in a bar 14 directly rearwardly of needle 13 and is vertically movable with the bar 14 between raised and depressed positions in a known manner. Head 11 is provided with the conventional thread tensioning and guide devices, drive mechanisms, feed dogs and the like, and the bar 14 slidably axially engages a bushing 16.

The thread retractor mechanism 10 includes a mounting block 17 in the form of a split collar having a longitudinal bore engaging the bushing 16 and firmly clamped thereto by a locking screw 17, engaging axially aligned transverse bores in the arms of the split collar block 17, one of the bores being tapped and the other counterbored. A pair of laterally spaced parallel rearwardly upwardly inclined side arms 18 and 19 are provided at their bottoms with forwardly directed fingers 20 which are secured to the side faces of mounting block 17 by screws 21. A cross-bar 22 having a central vertically extending tapped bore 23 extends between and is secured by screws 24 to the upper ends of arms 18 and 19. Formed in side arm 19 is a medial longitudinally extending straight guide slot 26, and formed in side arm 18 is a longitudinally extending cam slot 27 including a medial straight section 28 joining at its bottom a short downwardly rearwardly inclined section 29.

A linear actuator 32, shown in the form of a spring retracted compressed air cylinder, although other types of actuators may be employed, includes a cylinder member 33 provided at its inner end with a threaded axial sleeve 34 which tightly engages the bar threaded bore 23. Actuator 32 includes a spring retracted piston having an axial piston rod 36 slidably telescoping sleeve 34. The upper part of cylinder 33 is connected by way of a selectively or automatically actuated valve system of known construction, alternatively to a compressed air source or exhaust.

A slide block 37 is positioned between arms 18 and 19 and has a tapped longitudinal bore engaging the threaded end of piston rod 36, and firmly locked thereto by a nut 38 engaging the piston rod threaded end and bearing on the upper face of slide block 37. An arm 39 projects from the upper part of block 37 toward side arm 19, and is provided with a tapped transverse bore engaged by a screw 40 which projects through slot 26 and supports an axial roller 41 in longitudinal slidable engagement with guide slot 26.

A transverse bore 42 is formed in the lower part of block 37 and a shaft 43 projects through and is journalled in the bore 42. One end of shaft 43 underlies ear 39 and is provided with an enlarged cylindrical head 44 having a diametric bore 46 and a medial slit delineating opposite clamp arms on opposite sides of bore 46. The clamp arms are provided with aligned bores 47 in quadrature with an outside bore 46, one of the bores 47 being tapped, bores 47 being engaged by a screw to permit the tightening of the clamp arms.

The end of shaft 43 opposite to enlarged head 44 has rigidly attached thereto a radially extending crank arm 48 having an enlarged split collar at its lower end 49 which collar is clamped to the shaft 43. The crank arm 48 extends upwardly from shaft 43 and is provided proximate its free end with a tapped bore 50 engaged by a screw 51 which carries a freely rotatable followerdefining roller 52 in sliding engagement with cam slot 27.

A retractor or picker arm 53 is supported by and movable with shaft head 44 and is formed of stiff wire or rod which, except for the outer free end, is enclosed in a plastic sheath 54. The picker arm 53 includes a substantially straight upper leg 56 whose upper end engages and is clamped in bore 46 of head 44, and which depends from head 44 and is laterally offset to the right of the path of needle 13 as viewed in FIG. 1. Projecting forwardly from the lower end of leg 56 is an intermedi ate leg 57 which joins at its forward end a depending leg 58 which is slightly inclined to the left. The leg 58 terminates in an integrally formed hook member 59 which is rearwardly open and includes an end leg 60 which is longitudinally aligned across the reciprocating path of the needle 13, and is inwardly and rearwardly inclined from its base so that with the forward movement of the hook member 59, the thread depending from the raised needle 13 is engaged by hook leg 60 and laterally displaced until the hook member 59 advances forwardly of the needle path.

Considering now the operation of the thread wiping mechanism described above, under normal sewing conditions the cylinder 32 is exhausted and piston rod 36 is retracted thereby to raised positions as shown in FIGS. 1 and 2. Under the above conditions, followers 41 and 52 register with the upper ends of slots 26 and 27 respectively so that the picker arm 53 is rearwardly swung and the hook member is in a raised position, rearwardly of the needle 13 and completely outside the sewing or operating space of the sewing machine.

Upon completion of a sewing operation with the picker arm in its retracted position, the needle 13 is stopped in its fully raised position and the needle thread T depending from the needle 13 is cut either manually or automatically. Thereafter, cylinder 32 is sequentially connected either automatically or manually to compressed air and then to exhaust thereby successively to lower and to raise piston rod 36 and slide block 37. With the lowering of the slide block, the picker arm 53 which is carried by the shaft 43 is lowered, and during the initial major portion of its depression, does not rock since the follower engaged slots 26 and 27 are parallel. When the picker arm 53 reaches a depressed position at which the lower section 29 of slot 27 is engaged by follower 52, the hook member 59 is at a level between the bottom of raised needle 13 and foot piece 15. At the slide block 39 is further lowered by piston rod 36, the follower traverses slot section 29 to rock shaft 43 clockwise by way of arm 43 thereby to swing picker arm 53 and hook member 59 forwardly across the path of needle 13. With the forward movement of hook member 59, the thread T depending from needle 13 is momentarily laterally displaced by hook leg and returns into alignment with the opening of hook member 59 to finish the advance stroke of the mechanism.

The cylinder 32 is then connected to exhaust and the piston rod 36 is spring returned to its raised position, and the picker arm 53 and the hook member 59 thereby effect a motion opposite to that effected with the advance stroke of the piston rod 36. Upon the rearward movement of hook member 59, the cut thread T is engaged and moved rearwardly and then upwardly with the raising of the picker arm 53 to complete the cycle and withdraw the thread from the sewing area.

While there has been described and illustrated a preferred embodiment of the present invention, it is apparent that numerous alterations, additions and omissions may be made without departing from the spirit thereof.

1 claim:

1. In a sewing machine including a needle reciprocatable along a path between a raised and a lowered position, a thread wiping mechanism comprising a picker member including a hook element having a rearwardly directed opening and actuating means disposed rearwardly and above said needle path and supporting said picker member for successively lowering said picker member toward said needle path, rocking said picker member to advance and retract said hook member across said needle path and then retracting and raising said picker member above the path of the lower end of said needle.

2. The thread wiping mechanism of claim 1 wherein said actuating means comprises a slide member recip rocatable between raised and lowered positions, said picker member being swingably supported by said slide member, a stationary member and a follower coupled to said picker member and engaging said stationary member along the lower path of said slide member to swing said picker member forwardly and rearwardly with the lowering and raising of said slide member proximate the bottom of its path.

3. The thread wiping mechanism of claim 2 wherein said picker member includes an elongated arm extending downwardly from said slide member and terminating in said hook element.

4. The thread wiping mechanism of claim 3 wherein said actuating means comprises a transverse shaft journalled to said slide member and supporting said picker member, and a crank arm secured to said shaft and supporting said follower eccentrically to said shaft.

5. The thread wiping mechanism of claim l wherein said actuating means comprises a pair of transversely spaced parallel vertically extending side arms disposed,

on said slide member and engaging said second slot, said picker member including an arm extending from said shaft and terminating in said hook member, and means for reciprocating said slide member.

6. The thread wiping mechanism of claim 5 wherein said slide member reciprocating means comprises a pneumatic cylinder having a piston rod connected to said slide member. 

1. In a sewing machine including a needle reciprocatable along a path between a raised and a lowered position, a thread wiping mechanism comprising a picker member including a hook element having a rearwardly directed opening and actuating means disposed rearwardly and above said needle path and supporting said picker member for successively lowering said picker member toward said needle path, rocking said picker member to advance and retract said hook member across said needle path and then retracting and raising said picker member above the path of the lower end of said needle.
 2. The thread wiping mechanism of claim 1 wherein said actuating means comprises a slide member reciprocatable between raised and lowered positions, said picker member being swingably supported by said slide member, a stationary member and a follower coupled to said picker member and engaging said stationary member along the lower path of said slide member to swing said picker member forwardly and rearwardly with the lowering and raising of said slide member proximate the bottom of its path.
 3. The thread wiping mechanism of claim 2 wherein said picker member includes an elongated arm extending downwardly from said slide member and terminating in said hook element.
 4. The thread wiping mechanism of claim 3 wherein said actuating means comprises a transverse shaft journalled to said slide member and supporting said picker member, and a crank arm secured to said shaft and supporting said follower eccentrically to said shaft.
 5. The thread wiping mechanism of claim 1 wherein said actuating means comprises a pair of transversely spaced parallel vertically extending side arms disposed rearwardly and above said needle path and having formed therein first and second guide slots having parallel linear upper sections, said first slot having a cam defining lower section angularly related to said slot upper section, a slide member slidably disposed between and movable along said tracks, a transverse shaft journalled to said slide member, a crank arm mounted on said shaft, a first follower located on said crank arm and engaging said first slot, a second follower located on said slide member and engaging said second slot, said picker member including an arm extending from said shaft and terminating in said hook member, and means for reciprocating said slide member.
 6. The thread wiping mechanism of claim 5 wherein said slide member reciprocating means comprises a pneumatic cylinder having a piston rod connected to said slide member. 